Major aortopulmonary collateral arteries (MAPCAs) are frequently present in patients with cyanotic congenital heart disease and reduced pulmonary blood flow such as severe tetralogy of Fallot (TOF). Large or multiple collaterals can result in pulmonary overperfusion and congestive heart failure during the post-operative period of corrective surgery. Surgical ligation of MAPCAs can be difficult because of technical limitations. Transcatheter occlusion has emerged as the preferred strategy of management of MAPCAs. We report the case of a pediatric patient with TOF who showed refractory heart failure due to MAPCAs shortly after a successful corrective operation. Transcatheter Amplatzer vascular plug and detachable coil occlusion of MAPCAs was successfully performed and resulted in a favorable clinical recovery.
A 10-year-old boy who had previously undergone surgery for TOF was referred for cardiac catheterization at our catheter room because of recurrent exertional dyspnea for 5 months, and aggravated for 2 weeks. His medical history revealed that he had successfully undergone surgical correction for TOF 6 months ago. However, he had experienced recurrent exertional dyspnea and right pleural effusion in the early post-operative period. Post-admission echocardiography revealed that all the chamber of heart was enlarged, especially the right ventricular (49 mm). In addition, a severe pulmonary regurgitation was also observed on the echocardiography. Cardiac catheterization detected a right ventricular pressure of 54 mmHg, pulmonary artery pressure of 40 mmHg, and oximetry showed significant left-to-right shunt at the level of the pulmonary artery with a calculated pulmonary-to-systemic flow ratio (Qp/Qs) of 1.8:1. Selective angiography of the anonyma and left subclavian arteries revealed that there were 2 large tortuous MAPCAs arising from the anonyma (Figure 1A) and the left subclavian artery (Figure 1B), and they flowed into the right and left pulmonary arteries, respectively. An angiogram in the upper descending aorta demonstrated many aortopulmonary collaterals supplying both lungs (Figure 1C). A “competitive flow” phenomenon in the right upper pulmonary artery was observed at right ventriculography, which suggested that the retrograde pressure provided by the MAPCAs exceeded antegrade pressure. In view of these MAPCAs are the leading cause that responsible for post-operative heart failure, transcatheter occlusion of these MAPCAs was performed. We passed a 6-French Judkins Right 3.5 (Cordis Corp., USA) guiding catheter over a 260 cm, 0.035-inch hydrophilic coated guide wire (Terumo, Japan) into the largest collateral artery (originating from the anonyma), a 10-mm Amplatzer vascular plug was chosen to be approximately 50% greater than the diameter (6.5 mm) of the target vessel, and the Amplatzer vascular plug was advanced via the guiding catheter and deployed when satisfactorily positioned. Repeated angiogram in the anonyma 15 minutes after plug deployment confirmed that this collateral artery was completely occluded at the plug level (Figure 2A). The plug was then released from the cable. Similarly, another 6-mm Amplatzer vascular plug (approximately 40% larger than the diameter of the target vessel) was deployed at the collateral artery stemming from the left subclavian artery and complete closure was also acquired (Figure 2B). To obliterate the collateral vessel that originating from the right side of the descending aorta, we advanced a 5 mm×5 mm detachable coil (COOK, USA) to the narrowest segment (Figure 2C). After the procedure, the pulmonary oxygen saturation decreased from 89% to 80%. Repeated right ventriculography confirmed that the competitive flow phenomenon had disappeared. No procedure related complications such as dysphagia, hoarseness, and hemoptysis were observed. The patient was discharged 1 week later with a good clinical status. On follow-up at 12 months, he was asymptomatic and without any pharmacologic support. Chest radiography showed normal lung fields and echocardiography showed that the diameter of the right ventricular was 24 mm, left ventricular 32 mm, and the left ventricular ejection fraction was 62%. Serial clinical and auxiliary examination evaluations confirmed that the patient no longer had cardiac volume overload.
Multiple MAPCAs can be deleterious at the time of post correction of TOF because excessive pulmonary blood flow contributes to symptomatic cardiac volume overload. In our patient, the resulting refractory congestive heart failure was not expected pre-operatively. This finding emphasizes the importance of early identification and interruption of hemodynamically significant MAPCAs to avoid such complications in similar cases. Routine pre-operative angiocardiography for identifying MAPCAs is reasonable in complex congenital heart disease patients, particularly in those with echocardiographic evidence of pulmonary artery dysplasia.1 The presence of MAPCAs should be ruled out whenever a post-operative course after a successful surgical correction is unexpectedly complicated by cardiac failure, even if a presurgical angiography fails to show them.2 In this setting, selective aortic angiography is the preferred imaging tool for detailing MAPCAs. Non-invasive alternatives such as contrast-enhanced magnetic resonance angiography and multidetector-row computed tomography are also useful for assessment of MAPCAs.3
Transcatheter occlusion is currently the preferred method for the management of MAPCAs.4 Of note, the device for occlusion should be selected according to angiographic features of the target vessels. In our case, the 2 MAPCAs arising from the anonyma and left subclavian arteries were characterized by the finding that they were exceedingly tortuous, which made it difficult to advance a traditional large delivery sheath to the ideal point; therefore, the use of the traditional Amplatzer occluder was inappropriate. These target vessels were also too large to be safely occluded with coils. Considering these limitations, we selected the recently developed Amplatzer vascular plug for occlusion. The Amplatzer vascular plug offers attractive characteristics over other conventional Amplatzer devices; it is made from densely woven Nitinol mesh wires and has no occlusive fabric material inside it, which gives it a lower profile. Such an exclusive design allows it to be delivered via small catheters such as standard 5-8 French coronary guiding catheters.5 The collateral vessel originating from the right side of the descending aorta was relatively small in dimension, and there was a stenosis located in the middle of it. Therefore, this target collateral vessel could be effectively and safely occluded with a detachable coil. After occlusion procedure, the hemodynamic status was significantly improved, as evidenced by the pulmonary oxygen saturation, pulmonary artery pressure and pulmonary to systemic flow ratio were decreased, while systemic artery pressure and oxygen saturation were elevated. Therefore, a favorable clinical recovery was achieved in this patient.
It is worth noting that contraindications of transcatheter occlusion include patients in whom the responsible collateral arteries directly supply a large area of pulmonary parenchyma, when embolization could result in infarction of the lung parenchyma.1 Therefore, prior to performing transcatheter occlusion, careful analysis should be made based on the collateral circulation to ensure that the aortopulmonary collateral arteries targeted for embolization are not the sole source of blood flow to a parenchymal segment.
Transcatheter occlusion of MAPCAs after surgical correction for TOF is an effective strategy for post-operative congestive heart failure and can result in a favorable clinical outcome.
The authors thank Dr. SHEN Xiang-qian and Dr. FANG Zhen-fei for their invaluable help in planning the strategy during the procedure.
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